One specific area where pipelines are used extensively is in the transporting of liquid from bulk storage tanks. Many types of liquids are stored in bulk, both above ground and underground. A special problem exists with the pipelines used in connection with underground storage tanks. Since pipelines do not last forever, due to normal deterioration or damaging external forces, they are always susceptible to leakage. If the liquid being conveyed is a danger to the environment or the health when not controlled, substantial damage can occur before the leak is even detected. For examp1e, storage tanks are used extensively for storing liquid gasoline at retail gasoline stations. Necessarily, these stations are in populated areas and therefore there is always a danger associated with leaks from the tanks or pipelines associated therewith. Any leaks which develop are normally very slow initially. This means that the leak is difficult to detect until a substantial amount of gasoline has leaked. By that time environmental damage and possible health problems have occurred.
The time and expense needed to clean up a gasoline spill can be enormous. The ground surrounding the pipeline would have to be decontaminated, a procedure which could be extensive in case of a slow leak which is not detected early or a sudden large leak. In addition to the expense of the above clean-up, there is the loss of profits due to the down-time involved not only with the damaged pipeline, but also possibly with the whole gasoline station. The health hazards associated with a gasoline spill can also be enormous in case of an accidental fire or drinking water contamination.
Underground pipelines are particularly troublesome in those areas that are prone to earthquakes. Typical pipelines are constructed of metal or rigid plastic. Any earthquake is likely to cause a crack in the pipeline with a consequent leak. If the leak is slow, the same problems as above discussed exists. If the leak is fast, the problem is readily detected, but only after the ground has been contaminated.
The problems associated with the present pipelines are well known. One attempt to solve the known problems has been the use of double walled systems. In this type of system the rigid pipeline is surrounded by a rigid shell which acts as a containment vessel if the pipeline develops a leak. A slow leak in the pipeline is satisfactorily contained. However, in those areas prone to earthquakes, it is quite possible the pipeline and the shell would both be damaged. In my previous filed patent application, Ser. No. 06/731,968, there is disclosed a jacketed pipeline system. The jacket is flexible which allows for ease of installation and provides a measure of earthquake protection not possible with rigid jackets.
Installation of a rigid jacket over a rigid pipeline which is to be part of gasoline storage tank pipeline system is best accomplished when the storage tanks and pipeline system is first installed. Retrofitting an existing rigid pipeline system with a rigid jacket is very difficult. This is because a typical pipeline system is comprised of several bends of greater than 30 degrees and various points where three or even four pipelines meet to form a junction. Sliding a solid rigid jacket over a rigid pipeline having a bend can not be done. The problem of how to readily enclose a pipeline junction is virtually insurmountable.
There has now been discovered split fittings useful in a jacketed liquid pipeline system which solves many of the problems inherent with the existing systems. The jacketed system of this invention is economical and readily retrofitted over existing pipeline systems having a series of bends and/or junctions.